Drilled a 6mm hole as can be seen in the picture, 6mm x 20mm s/steel bolt and nut, 2 x s/steel tank washers, earthed the neg terminal of the compressor to this bolt, liberal coat of ACF-50 anti-rust fluid all around the washers and drilled hole. The Stebler has a slotted mounting point, I used that.
Didn't use a relay, never have done and not had a problem of the fuse blowing.
PS, thinking back, I think I spaced down the mounting of the compressor to stop it fouling the body.